This excerpt taken from the EQR 10-K filed Mar 8, 2006.
See Item 7 for a reconciliation of net income to FFO.
(2) The Company believes that FFO is helpful to investors as a supplemental measure of the operating performance of a real estate company, because it is a recognized measure of performance by the real estate industry and by excluding gains or losses related to dispositions of depreciable property and excluding real estate depreciation (which can vary among owners of identical assets in similar condition based on historical cost accounting and useful life estimates), FFO can help compare the operating performance of a companys real estate between periods or as compared to different companies. FFO in and of itself does not represent net income or net cash flows from operating activities in accordance with GAAP. Therefore, FFO should not be exclusively considered as an alternative to net income or to net cash flows from operating activities as determined by GAAP or as a measure of liquidity. The Companys calculation of FFO may differ from other real estate companies due to, among other items, variations in cost capitalization policies for capital expenditures and, accordingly, may not be comparable to such other real estate companies.